Floaters and flashes are all associated with the retina. This thin, clear tissue lines the back of the eye. It is made of sensitive nerve cells that capture light like the film in a camera. The picture the eye sees is sent from the retina through the optic nerve to the brain, which interprets it. A thick, clear (vitreous) gel in the eye fills the cavity behind the lens. This gel lies next to and is loosely attached to the retina.
If you have friends over 40, ask them about floaters. Many have likely noticed them in their vision.
Floaters, formed inside the vitreous gel of the eye, are condensations of the protein gel. They come in all shapes and sizes. Some look like squiggly lines, others are just round dots, and some have exotic shapes like flies, spider webs, veils or clouds. All can be a normal part of aging.
Floaters are a bother because they float around in the cavity of the eye, casting a shadow on the retina and momentarily interfering with vision. However, after a few weeks the brain recognizes the floaters and notices them less. We are advised to make friends with our floaters and ignore them.
Floaters are more noticeable when background light is bright. You may see them when looking at big sunny windows, clear blue skies or on snowy white days.
Reducing brightness and glare helps. Use an indirect reading lamp, tinted lenses with an antireflection coating, or just control the room lighting with blinds. It is unusual for floaters to be so numerous or dense that they significantly affect vision.
Though young people may notice floaters, they become more common as we age. Being short sighted, having diabetes or going through cataract surgery makes us more likely to spot them. As we get older, the vitreous gel changes into a more watery material and becomes thinner. The vitreous can eventually collapse and separate from the retina. This separation is called a posterior vitreous detachment.
Separation may pull on and tear the retina, or hemorrhage (bleed). After a posterior vitreous detachment, floaters may seem to move more quickly because the vitreous gel is no longer sticking to the retina. Nothing can be done to prevent this detachment, nor is there any satisfactory treatment.
Sometimes floaters are associated with eye inflammation, hemorrhages or trauma rather than aging.
If the vitreous shrinks, it may pull on the retina. This pulling stimulates photo receptor cells in the retina. The resulting flashes of light may vary from mild flickering to bolts of lightning. Such flashes are usually brief (a few seconds) and rarely last for more than a few weeks.
At first, floaters and flashes can be alarming. It is very important to see an ophthalmologist right away for a complete assessment of the retina. In many cases, they are not serious. However, they sometimes indicate more serious problems.
Using drops that dilate (open) the pupil and equipment with bright lights, the ophthalmologist will look for a hole or tear in the retina or more serious problems.
Small tears or holes can lead to retinal detachment. If a hole is in the retina, vitreous fluid may pass through and flow between the retina and the back wall of the eye. This can separate the retina from the back of the eye, so it detaches. Since the detached part of the retina will not work properly, a blurry or blind spot appears in the field of vision. A detached retina is painless and cannot be seen from the outside of the eye. In this case, urgent ophthalmological care and referral to a retinal specialist is necessary. Although laser therapy may treat retinal holes or tears, surgery may be needed to prevent or repair a detached retina.
If retinal hemorrhage or bleeding has also occurred, you might notice thousands of little spots or a haze in your vision. Such symptoms also indicate you should see an ophthalmologist right away.
Although floaters and flashers are often harmless, see your ophthalmologist when they first appear. Chances are you have no reason for concern.